Just how small are atoms? And what's inside them? The answers turn out to be astounding, even for those who think they know. This fast-paced animation uses spectacular metaphors (imagine a blueberry the size of a football stadium!) to give a visceral sense of the building blocks that make our world.
Here are some good, detailed resources on atoms:
• http://www.chemguide.co.uk/atoms/properties/atomorbs.html#top
• http://ocw.mit.edu/courses/chemistry/5-112-principles-of-chemical-science-fall-2005/video-lectures/lecture-6-schroedinger-equation-for-h-atom/
• http://ocw.mit.edu/courses/chemistry/5-112-principles-of-chemical-science-fall-2005/video-lectures/lecture-7-hydrogen-atom-wavefunctions/
An atom smasher, or particle accelerator, collides atomic nuclei together at extremely high energies, using engineering that exploits incredibly cold temperatures, very low air pressure, and hyperbolically fast speeds. Don Lincoln explains how scientists harness the power of both electric and magnetic fields to smash atoms, eventually leading to major discoveries about the matter in our universe.

What do macaroni salad and gasoline have in common? They are made of exactly the same stuff -- specifically, the same atoms, just rearranged. So, while we put the former in our mouths and the latter in our cars, they are really just variations on the same atomic theme. Josh Kurz breaks macaroni salad down to its smallest chemical components.
How did the periodic table of elements revolutionize our understanding of the world? What scientists contributed to the table we have today? Eric Rosado discusses the key people and discoveries that have molded our understanding of chemistry today.
Here's a video for every element on the periodic table of elements.